LAGOS, Nigeria – LAGOS, Nigeria (AP) — Pirates armed with Kalashnikov rifles clashed with Nigerian navy forces in a failed bid to take over an offshore oil platform, then kidnapped three French employees of a marine services company while retreating, a Nigerian official said Wednesday.

Navy Commodore David Nabaida said a Thai employee also may have been taken hostage by the pirates during the attack, which began early Wednesday morning.

The French-flagged vessel Bourbon Alexandre was working in an offshore oil field operated by Addax Petroleum, a subsidiary of Chinese state-owned oil producer Sinopec Group.

It was the latest act of piracy in the Gulf of Guinea, especially along Nigeria's 530-mile (850-kilometer) coast. Such pirate and militant attacks have been common near Nigeria's Niger Delta, an oil-rich region of swamps, mangrove fields and creeks almost the size of South Carolina. However, it is highly unusual for attackers off Nigeria's coast to try to mount a floating oil platform.

No claim of responsibility for the attack has been made, officials said. The Movement for the Emanicipation of the Niger Delta, the main militant group fighting the government in the region, issued a statement late Wednesday night to The Associated Press saying its members were "in negotiations with the abductors" to have them released into their care.

"When this is done, we will be in a better position to give further information about their state of health and the duration of their stay with us," the statement read.

Africa's most populous country is full of oil barges and oil company ships off the delta, one of the top sources of crude oil for the United States. Cargo ships off Lagos, Nigeria's largest city, also often face pirate attacks as they wait to unload their goods at the city's busy and chaotic ports.

The kidnappings came a week after five French citizens working at a uranium mine in Niger were abducted, along with two African workers. Responsibility for those abductions last Thursday has been claimed by al-Qaida in the Islamic Maghreb, a branch of the global terror network that operates in Algeria and the vast Sahel region. There was no apparent link between the two incidents.

The pirates attacking the oil platform became locked in a sustained firefight with Nigerian naval forces after one of its patrol boats intervened, Nabaida told the AP. The pirates nearly reached the platform by using a vessel that looked like the ships that routinely provide supplies to workers onboard, he said.

The pirates captured the three French employees from the Bourbon Alexandre, then fled in the speedboats, he said. The ship's 13 other crew members "remained aboard, and no injuries were reported," the company said. It made no mention of a Thai employee taken hostage.

"We're tracking them to see if we can intercept them," Nabaida said of the pirates. No ransom demand had been made, but investigators suspect they know the group responsible for the attack, Nabaida added, without elaborating.

The pirates fell back to regroup during the firefight with the Nigerian naval forces, then returned with additional speedboats, the naval spokesman said. As the sun rose Wednesday, the pirates gave up their attack and turned to escape while the navy awaited reinforcements. The Bourbon vessel appeared and the attackers took it over, Nabaida said.

Bourbon said the families of the hostages have been contacted. It would not provide the nationalities of the other crew members.

France's Foreign Ministry confirmed the three kidnappings and said it was in close contact with Nigerian authorities, Bourbon company officials and the victims' families. "We are fully mobilized in Paris as in Abuja to obtain their liberation," the ministry said in a statement.

Sinopec purchased Addax Petroleum, a Geneva-based oil and gas explorer, last year for $7.2 billion. Addax has rights to explore five offshore locations in Nigeria, some shared with other firms.

Both Addax and Bourbon have been targeted before by militants operating near the Niger Delta. In June 2008, two attacks on Addax security escort ships killed at least two Nigerian sailors and wounded several others. In October the same year, pirates near Cameroon's border with Nigeria kidnapped 10 Bourbon workers, all of whom were later released.

Pirates also kidnapped and later released nine Bourbon workers seized off Nigeria's coast in January 2009.

The Bourbon Alexandre is an Anchor Handling Tug Supply vessel, a type of ship designed to supply oil rigs and tow them to location.

The French Foreign Ministry warned last month of an increase in the kidnappings of foreigners throughout Nigeria.

Militants in the delta have kidnapped oil workers, bombed crude pipelines and fought with government troops since an insurrection began there in 2006. While a government-sponsored amnesty has slowed violence in recent months, analysts worry that the program has begun to fray as weapons remain plentiful in the impoverished region.

Most oil hostages are released without injury after some sort of a ransom is paid. In July, pirates released 12 foreign sailors taken hostage off Nigeria's coast unharmed.

The International Maritime Bureau, which tracks piracy worldwide, reported 28 attacks off Nigeria's coast during 2009. The bureau believes at least another 30 pirate attacks went unreported, due to company fears about higher insurance premiums or unwanted publicity.

Bourbon SA operates support vessels for offshore oil rigs and provides repair, inspection and maintenance services for undersea oil fields, and has a smaller unit that ships commodities like coal, grain and timber worldwide. The company had revenues of euro960 million ($1.28 billion) last year.

___

Associated Press Writer Greg Keller reported from Paris.

Get all the stories you need-to-know from the most powerful name in news delivered first thing every morning to your inbox